This double blind, placebo controlled Phase 3 study has been designed to evaluate the efficacy, safety and tolerability of Arikace™ in treating CF patients with chronic bronchopulmonary infection. Eligible subjects will be randomized 1:1 to receive 590 mg of Arikace™ or placebo once daily using a PARI Investigational eFlow® Nebulizer. Subjects will receive 28 days of treatment and will then be followed for safety for 56 days. Total study duration is up to 102 days (~3 months) including an up to 18 day Screening period. Subjects will be evaluated for safety, tolerability and efficacy bi-weekly throughout the study. Pharmacokinetics (PK) of Arikace™ in blood, sputum and 24-hour urine will be determined in a subgroup of study subjects who consent to PK evaluation.